I'd probably get the most top range Dean or one of John Petrucci's sig Ibanez.

EDIT: ^That's a damn nice guitar.

good luck finding one of the JPM Ibanez, amazing guitar though. I'd also recommend an esp for pure metal. I used to like Jacksons, but they seem to be going downhill imo. Besides esp, schecter are also good for metal, ibanez is very versatile so you can't really go wrong with those, even though they aren't pure metal.

If u buy an ESP, i'd also recommend one of the Eclipse (or EC - LTD)
If u go for schecter, get the C-1 hellraiser
Ibanez i really like the s series (i own one), but rgs are also good guitars.

__________________
“If there are no stupid questions, then what kind of questions do stupid people ask? Do they get smart just in time to ask questions?” - Scott Adams

2: if you have the right amp, as long as the guitar is made of decent, solid wood and has a good bridge pickup, you're good to go.

This is probably the correct answer. Also, the guitar should be comfortable to play, but that is of course a matter of personal preference. There is no "ultimate metal guitar", even though a lot of people might tell you so.